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Old 09-17-2007, 10:08 AM   #1
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Default 20% to 30% nitro switch ??

Has anyone switched from 20% to 30% nitro ?? and did you have to richen up the motor? Ive heard different stories. Ive heard it runs coller with 30% but i thought thats cause you fatten up the motor due to the extra power, is that a false rumr as well?? Im concerned with fuel mileage, if i have to fatten up and loose mileage its not worth it, but ive been told the power feel is worth it..
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Old 09-17-2007, 10:21 AM   #2
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i did b4. now i only run 30%.

yes 30% does cool better, being higher in nitor %. and nitromethane naturaly is cool, like alcohol due to the fast evaporation of it.
you ll likely need to add one headshim ( assuming your on 20% now) to the motor to gain a bit of internal combustion chamber volume.
you can typicaly run a touch leaner with 30% but i dont personally.

when i moved from traxxassssss 20% to byrons orig 30% on the Hot Bodies Lightning 26 motor i had, i lost around 25 to 35*F in temps. instead of it running around 270, it was closer to 240. as well as had more power thru the whole rpm range.

also once you go up in nitro %, you dont want to try to go back down.
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Old 09-17-2007, 10:33 AM   #3
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30% Nitro runs cooler because nitro carries oxygen, more nitro=more oxygen. Because of this extra oxygen you must run richer settings to get the mix right, more air/fuel=more power. You will also notice that 30% fuels usually have a lower percentage of oil but this is also because there is more overall fuel passing through the engine so less of the total amount needs to be oil and the overall amount of oil going through the engine winds up being the same. If you have a .21 engine that was made for U.S. sale it will probably be shimmed ok for 30%, most .12-.15s are intended to be used with 20%.
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Old 09-17-2007, 11:16 AM   #4
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thanx for the detailed response, do you know how it would effect the fuel mileage, (2nd question in my post)..
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Old 09-17-2007, 08:37 PM   #5
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sounds like i need to chim in here as i have some experience on this...

ok so i started running traxxas fuel 20% when i first bought my rc. then after that gallon was gone i jumped up to 33% fuel with 12% oil and it now goes like a raped ape but the fuel mileage does get a bit worse but not much. you do have to tune ur engine for it to except the 30% fuel. if ur going to jump to 30% make sure u have at least 12% oil. good luck with the decision.. i love the 33% over the 20%.
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Old 09-18-2007, 10:09 AM   #6
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Quote:
jabroni racing
thanx for the detailed response, do you know how it would effect the fuel mileage, (2nd question in my post)..
The fuel mileage will be less, cause you' re running richer.
At least, that's my experience.
Didn't have to put additional shim on my Cobra.
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Old 09-18-2007, 06:51 PM   #7
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I run my 1/8 and 1/10 engines all on 30% sidewinder.
I checked and reshimmed the .12's and they've been going great all summer and I only need one fuel bottle now.
I just retuned the engine's when I switched till they felt good like I normally would. My temps and mileage didn't make much of a difference for me to really notice one way or the other.

All I can say Jay is try a gallon and see for yourself. You race enough to be a competent tuner and can then make your own observations.
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Old 09-18-2007, 07:01 PM   #8
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i run sidewinder also which i think is a great fuel might i add.when i switched from 20 to 30 i new i wasnt going back.as far as tune i just richend top and botton 1/4 turn and then retuned .
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Old 09-18-2007, 07:06 PM   #9
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Quote:
Originally Posted by jabroni racing View Post
Has anyone switched from 20% to 30% nitro ?? and did you have to richen up the motor? Ive heard different stories. Ive heard it runs coller with 30% but i thought thats cause you fatten up the motor due to the extra power, is that a false rumr as well?? Im concerned with fuel mileage, if i have to fatten up and loose mileage its not worth it, but ive been told the power feel is worth it..
I to switched to 30% TQ fuels from Byrons 20% that is still a good fuel they just don't carry it at my lhs anymore I'll i did was fatten up the top 3 hours and ran two tanks thru just on idle then leaned it back down 2 hours still have the Mccoy 59 plug in it and runs cool
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Old 09-19-2007, 09:10 AM   #10
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Jay whats up man? This is Marcus from Orlando, I pitted for you at this past years Losi race. Get up with Vernon Cook and get some of his Coldfusion fuel, its amazing. PM me if you do not have his number. You will love 30%.
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